Apparatus for casting molten metal under pressure



Feb. 23, 1932. R. H. v. cHRxsTENsEN APPARATUS FOR CASTING MOLTEN METALUNDER PRESSURE Filed Feb.

14, 1929 3 SheetS- Feb. 23, 1932.

,zlyww WLM, CM; XMM- Feb. 23, 1932. R. H. vA cHRlsTENsr-:N 1,846,087

APPARATUS FOR CASTING MOLTEN METAL UNDER PRESSURE Filed Feb. 14, 1929 3Sheets-$heet 3 nection with the pressure source.

Patented Feb. 23, 1932 UNITED STATES PATENT OFFICE APPARATUS IOR CASTINGIOLTEN METAL UNDER PRESSURE Application led February 14, 1929, SerialNo. 339,999, and in Denmark February 29, 1928.

This invention relates to die casting of molten metal under air or gaspressure and is especially adapted for use in gross pro duction ofcastings.

5 In this art it is known to use a casting reservoir or ladle in theform of a curved tube which is dipped into the crucible and one end ofwhich is permanently connected to a conduit which through a valve hascon- This arrangement, however, can involve disastrous accidents if thevalve leaks as the molten pressure source being arranged directly overthe gate of the mould. In this case a tight connection is obtainedwhereby that the ladle at the side opposite to the mouths of the tube isprovided with a boss against which pres sure is exerted. Thisconstruction, however,

is unpractical in many respects. For example it is diiicult to. obtaintightness at both ends of the curved tube, among other things on accountof the different heating of the co-acting parts.

According to the present invention the above named drawbacks areovercome whereby the connection between the pressure conduit, the ladleand the mould is estab lished by clasping the ladle between the outletof the pressure conduit and the gate of the mould. This can be performedby arranging the mouth of the pressure outlet and the mouth of the mouldate opposite each other in mutually mova le members, between which theladle can be clasped so that the cavity thereof will be opposite to bothsaid mouths.

According to the present invention the pressure with which the parts ofthe mould are forced together may be utilized to clasp the ladle, themember in which the mouth of the gate is arranged being for instancefreely movable so that it will be pressed against the ladle when themould parts are Figure 1 is a top view of an apparatus for 60 castingmolten metal under pressure using the method according to thisinvention,

Figure 2 is an end view, partly in section along the line II-II inFigure 1,

Figure 3 is a side view partly in section ce of the ladle of theapparatus, drawn on a larger scale,

Figure et is a cross section of the same on the line IVIV in Figure 3Figure 5 lis a side view of a modification 70 of the apparatus,

Figure 6 is la section of the same on the line VI-VI in Figure 5, and

Figure 7 is a longitudinal section of the ladle, appertainin to theapparatus shown 75 in Figures 5 and drawn on a larger scale. In Figures1 and 2, 10,11 and 12 are clamping members. The member 10 is secured atthe end of twotparallel rods 13 and 14while the two other members 11 and12 can slide 80 along said rods. The member 12 can be acted upon by twotoggles 15, which by means of gearings 16 are operated by a hand wheel17. The mould in which the metal is cast con' sists of two parts 18 and19 secured to the 85 members 11 and 12 respectively. The gate 20 of themould is continued through the member 11 and terminates in a detachablenozzle 21.

The molten metal is transferred from the crucible 27 to the mould 18, 19by means of a ladle 22 which is suspended to swing freely on a crank pinor pivot 23 carried by an varm 24. This arm is secured to one end of ashaft 25 journalled parallel to the rods 13 and 14. 95

The shaft 25 can be operated by a hand lever 26 at the opposite endthereof.

The crucible 27 is positioned in such a manner that. the ladle 22 can besubmerged into the crucible by swinging the shaft 25 through 100 onehalf revolution. The Crucible 27 is enclosed in a heat insulating,reproof casing 28 and is heated by means of an oil burner 29 of anyknown kind.

In addition to the crucible 27 the casing 28 encloses the lower part ofa boiler` 30 which is also heated by the burner 29, the furnace of theboiler being connected to the annular combustion chamber 33 surroundingthe Crucible by ducts 31 and 32. The heating of the boiler 30 can beadjusted by a displaceable damper 34 arranged in the duct 31.

From the steam space of the boiler 30@I conduit 36 provided with a valve35, Figure l, leads to the clamping member 10. In continuation of theconduit 36 a channel 37 is provided through the member 10. The openingof the channel 37 at the inner side of the member l0 terminates in anozzle 38. Y

l The cavity of the ladle 22 consists i1i`two compartments 39 and 40,Figures 3 and 4, interconnected below and having at the top an inlet 41for the pressure medium and an outlet 42 for the molten metal,respectively.

The inlet 41 and the outlet 42 are substantially aligned so that thecavity of the ladle can be interposed between the pressure conduit 36and the mould 18, 19 by clasping the ladle between the members 10 and11.

The compartment 39 is greater than the compartment40, and the cavity ofthe ladle 22 is so chosen that the ladle can deliver just a mouldcharge. Therefore to a certain apparatus there are a number of ladlesthe cavities of which are of different volumes and for a certain mould aladle is selected'the cavity of which corresponds to that of the mould.

The apparatus is used in the following manner:

By actuating the hand lever 26 theshaft 25 is rotated so that the ladle22 is swung until it is submerged in the molten metal in the Crucible27. During this movement the ladle- 22 hangs vertically down from thepivot 23 owing to the action of the gravity as the centre of gravity ofthe ladle lies below the point of suspension. Now the metal flows intothe cavity of the ladle through both openings 41 and 42. When the cavityhas been lled with molten metal the shaft 25 is swung in the oppositedirection until the ladle 22 assumes the position shown in Figure 1 inwhich thenozzle 38 is aligned with the inlet 41 and thenozzle 21 isaligned with the outlet 42. Then the toggles 15 are operated by means ofthe hand wheel 17 so that the mould parts 18 and 19 are pressed togetherand simultaneously the ladle 22 is clamped between the nozzles 38 and 21on the members 10 and 11 respectively. Finally the valve 35 is openedwhich causes the metal in the ladle 22 to be forced into the mould 18,19 which will be filled up by the metal as the air originally present inthe mould will be driven out through narrow apertures for this purpose,through which the metal can not pass.

In the embodiment shown in Fi res 5 and 6 the Crucible isarranged behindt e casting apparatus enclosed in a cas-ing 28a. The ladle 22a issuspended on a crank pin or pivot 23a on an arm 24a as in the previouscase, but in Figures 5 'and 6 the shaft 25a of the arm 24a is arrangedperpendicularly to the longitudinal direction of the apparatus andjournalledvin -a bearing 50. The ladle is transferred from the Crucibleto the mould and vice versa by the movement of the mould part 19a whichis moved when the castin is removed from the mould. To the mem er 12acarrying this mould part is adjustably secured a rod 51 the end of whichis formed as a rack 52 slidable in a guide 53, Figure 6.

The rack 52 meshes witha pinion or a toothed sector 54 secured to theend of the shaft 25a.

When the mould is in closed position, Figure 5, one end of the rack 52meshes with one end of the toothed sector 54 and the arm 24a assumessuch a position that the ladle 22a is situated between the nozzles 21aand 38a of the mould gate and the pressure conduit 36a respectively,with the inlet and outlet of its Cavity in connection with the mouths ofthe said nozzles, the exact position of the ladle being determined byadjustable screws 55 fixed to a yoke or strap 56 carried by the rods 13aand 14a. When the casting process has been performed the mould part 19ais removed from the other mould part 18a. During the first part of thismovement the rack 52 meshes with the sector 54 and the arm 24a' and theladle 22a are transferred tothe position shown in dotted lines in Figure5. In this position a projection 60 on the arm 24a rests against a fixedsto 57 which may be adjustable as shown. uring the further movement ofthe mould part 19a no co-action takes place between the rack and thetoothed sector.

It will be understood that theoretically it is suiicient that thegearing 52, 54 transfers the ladle from an end position to a position inwhich the centre of gravity of the ladle is beyond the axis of the shaft25a as the remainder of the movement may occur under the action ofgravity.

The means for moving the clamping member 12a consists in toggles 15a,gearings 16a and a hand wheel 17a as in the previous case.

The apparatus is supported by standards 58 which together with theCasing 28a are ar-V tid the metal surface in contact with the pressuremedium the pressure on the metal will increase when the surface of themetal passes from the part 39a to the part 395.- "I"he cross section mayvary otherwise than mdlcated 1n Figure 7. Generally according to thepresent invention the cross section of the branch connected to thepressure source varies in the longitudinal direction of the branch insuch a manner that the pressure on the metal will vary in accordancewith the desired progress of the casting process.

The ladle shown and described has the advantage that it can be removedand replaced by an other ladle if necessary. The 'ladle 1s very strongand can resist a conslderable pressure owing to it being block shapedexternall Frthermore it is advantageous that the Crucible be arranged sothat it can easily be removed and substituted by a crucible containing adiferent metal so that the casting of a new metal can be commenced in ashort period of time. The apparatus described does not require anyspecial shape or material of the crucible so that these factors can bearbitrarily chosen and existin crucibles and appurtenant furnaces may eused if desired. It is a feature of the apparatus that without anyalteration it can be used for casting all metals suitable for the art inquestion, the melting point of which lies below 1200 centigrades.

The invention is not restricted to the use of steam as a pressuremedium.

Having thus fully described my invention I claim as new and desire tosecure by Letters Patent:

l. In an apparatus for casting molten metal under pressure, a separateladle having two compartments connected below and extending upwards tothe same level and terminating in aligned inlet and outlet ducts, saidladle being adapted to receive molten metal when it is submerged intothe metal until the said ducts lie under the surface thereof.

2. ln an apparatus for casting molten metal under pressure, a mechanicalmovement adapted to transfer a ladle with aligned inlet and outlet ductsfrom a Crucible to a mould and vice versa, in such a manner that in eachposition during the transfer the inlet and outlet ducts of the ladle liesubstantially in the same horizontal plane.

3. ln an apparatus for casting molten metal under pressure, a castingreservoir with a substantially U-shaped cavity terminating inhorizontally aligned ducts, said reservoir being suspended to swingfreely at a point over its center of gravity.

4. in an apparatus according to claim 2, in which the said mechanicalmovement includes a crank mechanism with a horizontal crank pin on whichthe ladle is adapted to be suspended swingably.

5. In an apparatus for casting molten A i prising fixed abutments fordefining the end positions of the crank mechanism.

7. A casting reservoir for use in die casting, comprising a body with asubstantially U-shaped cavity having two branches, one of the saidbranches consisting of two parts, each of which -has a substantialconstant cross-section, the cross-section of the lower part beinggreater than that of the upper part.

8. An apparatus for casting molten metal under pressure, comprising aconduit having an outlet and adapted to be connected to a pressuresource, a mold having an inlet and adapted to be moved bodily in astraight path towards and away from the outlet of said conduit, acasting reservoir with a cavity serving to receive the molten metal anddebouching in oppositely directed ducts, said casting reservoir beingadapted to be moved bodily into and away from an operative positionbetween said outlet and said inlet, and means for bodily moving saidmold to thereby press the same against the casting reservoirtransmitting the pressure through the latter to outlet of said conduit.

9. The apparatus of claim 8, in which said conduit with its outlet isstationary and saidV mold comprises two separable mold parts one ofwhich is provided with said inlet, the said means for bodily moving themoldbeing adapted merely to act on the mold part not provided with theinlet whereby the other mold part provided with the inlet and saidcasting reservoir are clamped from opposite sides between said mold partnot provided with the inlet and said outlet of the conduit.

l0. An apparatus for casting molten metal under pressure, comprising aconduit having an outlet and adapted to be connected to a pressuresource, a mold having an inlet, said mold and conduit outlet beingrelatively movable in a straight path concentrically towards and awayfrom each other, a casting reservoir or ladle having an inlet duct andan outlet duct, means for bodily moving said casting reservoir from aposition suitable for the filling of the same with molten metal to anoperative position between said mold inlet and conduit outlet and viceversa, and means for relatively moving said mold and conduit outlettoward each other to clamp the casting reservoir therebetween when inits operative position.

l1. The apparatus of claim 10 in which said means "for bodily moving the'casting reservoir includes' a crank having a crank pin from whichsaidcasting reservoir is suspended.

12. An apparatus for casting molten metal under pressure, comprising aconduit having an outlet and adapted to be connected to a pressuresource, a mold adapted to be bodily moved in a straight path towards andaway from said outlet, a casting reservoir adapted to contain a chargeof molten metal and to be moved into and away from an operative positionbetween said mold and outlet and mold driving means for moving said moldin said straight path against .theD casting reservoir when in itsoperative position to thereby press the casting reservoir against thesaid outlet of the conduit whereby connection is not established betweensaid casting reservoir and outlet before the mold has engaged thecasting reservoir under the influence of said mold driving means.

In testimony whereof I have aixed my signature.

REINHARD'I' HARALD VALDEMAR CHRISTENSEN.

